package com.zll.framework.filters;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
/**
 * @author Administrator
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class SetCharacterEncodingFilter implements Filter {
 /**
  * 
  */
 public SetCharacterEncodingFilter() {
  super();  
 }
// ----------------------------------------------------- Instance Variables

  /**
   * The default character encoding to set for requests that pass through
   * this filter.
   */
  protected String encoding = null;

  /**
   * The filter configuration object we are associated with.  If this value
   * is null, this filter instance is not currently configured.
   */
  protected FilterConfig filterConfig = null;

  /**
   * Should a character encoding specified by the client be ignored?
   */
  protected boolean ignore = true;

  // --------------------------------------------------------- Public Methods

  /**
   * Take this filter out of service.
   */
  public void destroy() {
   this.encoding = null;
   this.filterConfig = null;
  }

  /**
   * Select and set (if specified) the character encoding to be used to
   * interpret request parameters for this request.
   *
   * @param request The servlet request we are processing
   * @param result The servlet response we are creating
   * @param chain The filter chain we are processing
   *
   * @exception IOException if an input/output error occurs
   * @exception ServletException if a servlet error occurs
   */
  	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
  		// Conditionally select and set the character encoding to be used
  		if (ignore || (request.getCharacterEncoding() == null)) {
  			String encoding = selectEncoding(request);
  			if (encoding != null) {
  				request.setCharacterEncoding(encoding);
  			}
  		}
  		// Pass control on to the next filter
  		chain.doFilter(request, response);
  	}

  /**
   * Place this filter into service.
   *
   * @param filterConfig The filter configuration object
   */
  public void init(FilterConfig filterConfig) throws ServletException {
  this.filterConfig = filterConfig;
   this.encoding = filterConfig.getInitParameter("encoding");
   String value = filterConfig.getInitParameter("ignore");
   if (value == null)
    this.ignore = true;
   else if (value.equalsIgnoreCase("true"))
    this.ignore = true;
   else if (value.equalsIgnoreCase("yes"))
    this.ignore = true;
   else
    this.ignore = false;
  }

  // ------------------------------------------------------ Protected Methods

    
  protected String selectEncoding(ServletRequest request) {
   return (this.encoding);
  }
}
